1. Field of the Invention
The present invention relates to a printing apparatus typically used in a printer, a facsimile and a copying machine, and more particularly to a printing apparatus with a guide member that guides a print medium to an eject roller.
2. Description of the Related Art
A printing apparatus that is used as a printer or a printing unit in a copying machine includes, for example, a serial type printing apparatus. The serial type printing apparatus forms an image on a sheetlike print medium such as paper and OHP sheet by gripping and transporting the print medium and scanning a print head over the print medium at a print position opposite a platen arranged on a print medium transport path. The print medium transport method generally employed by such a printing apparatus involves holding the print medium between a pair of rollers and rotating the rollers to feed the print medium. The pair of rollers is provided on both a paper feeding side and a paper discharging side of the printing apparatus. The rotation speeds of the paper feeding side rollers and the paper discharging side rollers are controlled in transporting the print medium.
Since the print position is provided between the paper feeding side rollers and the paper discharging side rollers, when a printing operation is performed, the print medium during an initial stage of printing is gripped by only the paper feeding side rollers. When, as the printing operation proceeds, the print medium comes close to the paper discharging side rollers, it is introduced into a nip portion of the paper discharging side rollers and held there.
Japanese Patent Laid-Open No. 2004-231389 describes the use of an eject guide to guide a print medium, that has been transported near the paper discharging side rollers, into the nip portion of these rollers.
FIG. 15 shows a relation between a conventional eject guide and a pair of rollers.
A paper eject roller 1510 has rollers 1510a, 1510b of different diameters extending axially (in a front-back direction perpendicular to a plane of the drawing). A print medium transported from a platen 1514 of FIG. 15 is held between the large-diameter roller 1510a and paper eject pinch rollers 1511a. The eject guide 1512 guides the print medium to a position near the roller 1510a and roller 1511a. 
One end of the eject guide 1512 is pivotally supported on a fulcrum 1513 of the platen 1514, with the other end supported on a circumferential surface of the small-diameter roller 1510b. In printing on print mediums of different thicknesses, the position of the platen 1514 is adjusted vertically in FIG. 15 to keep a distance between the print medium on the platen 1514 and the print head optimal. At this time, the eject guide 1512 pivots about the fulcrum 1513 at the first end with the second end supported on the circumferential surface of the small-diameter roller 1510b. With this construction, the print medium is always guided to a nip portion between the large-diameter roller 1510a and the paper eject pinch rollers 1511a. 
Installing such an eject guide 1512 in the printing apparatus, however, requires the small-diameter roller 1510b to be formed in the paper eject roller 1510 in order to support one end of the eject guide 1512. Considering a sliding contact with the eject guide 1512, the small-diameter roller 1510b of the paper eject roller 1510 needs to be formed of such materials as metals having a wear resistance. The large-diameter roller 1510a, on the other hand, needs to be formed of rubber and resin materials to secure a wear resistance against the print medium. Requiring the installation of the paper eject roller 1510 of such a complicated construction is detrimental to reducing the size and weight as well as the cost of the printing apparatus.